[DFDL-WG] xsd:any support - propose dfdl:initiatorLength property

[Steve Hanson]

Here's what we say about xsd:any (wildcard support) in DFDL spec.

Any Element Wildcard
The "any" element wildcard provides support for initiator-tagged data 
formats. 
The dfdl:initiatorSeparator property must be defined or it is a schema 
definition error.
The 'processContents' attribute is not allowed in DFDL 1.0 and it's use is 
a schema definition error.
This kind of wildcard is used to absorb content which while syntactically 
compatible is not logically modeled as elements of the sequence group. 
These declarations match a triplet of strings. The first is a 
variable-length string that matches any initiator tag. The second is a 
fixed value string which must match the initiator-separator property 
value. The third is a variable-length string that matches any content up 
until the end of the "element" being matched.
The length of data matching an any-element wildcard is specified by the 
usual length properties: dfdl:lengthKind, dfdl:lengthUnits, dfdl:length, 
dfdl:terminator. dfdl:initiator is not used by Any Element wildcards and 
is ignored if specified in scope. 

We insist on the presence of a known initiator separator to separate 
initiator from data. We should also allow initiator length, to support 
models where there is no separator. Exactly one of initiator separator and 
initiator length must be specified. Initiator length is not a valid DFDL 
property on any other xsd object. 

This is supported today by IBM's MRM parser.

Regards

Steve Hanson
Programming Model Architect
WebSphere Message Brokers
Hursley, UK
Internet: smh at uk.ibm.com
Phone (+44)/(0) 1962-815848





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